Display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with a graphical user interface.

The ornamental design which is claimed is shown in solid lines in the drawings. The outer perimeter broken line showing the display screen and all other broken lines showing text and FIGURES are included for the purpose of illustrating portions of the of the article and form no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 